A nickel-base superalloy, when it is used in a base material as a turbine blade or a turbine vane of a jet engine or the like, in many cases, is used with a surface of a base material coated to inhibit high temperature oxidation and heating. In this connection, even when the coating is peeled off for some reason, the nickel-base superalloy is expected to be an alloy excellent in the oxidation resistance so that an apparatus may not be immediately destroyed due to oxidation and may be used until a periodic inspection.
Among conventional nickel-base superalloys, a Rene N5 alloy (an alloy made of Co: 8% by weight, Cr: 7% by weight, Mo: 2% by weight, W: 5% by weight, Al: 6.2% by weight, Ta: 7% by weight, Hf: 0.2% by weight, Re: 3% by weight and Ni as a balance) is known as an alloy excellent in the oxidation resistance (see patent literature 1).
However, with a recent advance in jet engines and gas turbines, a fuel gas temperature becomes further higher. Accordingly, a nickel-base superalloy having further excellent oxidation resistance is expected to realize.    Patent literature 1: U. K. Patent No. GB-2235697A